A prior technology temperature sensor apparatus is described in U.S. Pat. No. 7,439,601. The device disclosed therein sums two currents and then drives another resistor. By definition the voltage representing the temperature (Vtemp) is interrelated to the temperature coefficient of the voltage (TCVtemp) representing the temperature (Vtemp). Therefore Vtemp and d(Vtemp)/dTemp are not independent of each other.